Species

Carmichaelia williamsii

Etymology

Carmichaelia: after Carmichael, a botanist

Common Name(s)

William's Broom, Giant-flowered broom

Current Conservation Status

2012 - At Risk - Relict

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Flora Category

Vascular - Native

NVS Species Code

CARWIL

The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.

Structural Class

Dicotyledonous Trees & Shrubs

Synonyms

None

Distribution

Endemic. North Island only, where it known mainly from northern offshore islands (particularly the Poor Knights and Alderman Islands) to East Cape. On the mainland it is now known from only two small remnant populations near East Cape.

Habitat

A strictly coastal species of open forest, scrub, cliff faces and talus slopes.

Similar Taxa

This is the only yellow-flowered native New Zealand broom, and may be distinguished from the common introduced broom (Cytisus scoparius (L.) Link) by the non-leafy, light green, much wider, flattened branches, the larger, pale-yellow flowers with purple or red veins, and the late-winter flowering habit.

Flowering

From July and October, though sporadic flowering may occur throughout the year.

Flower Colours

Green,Yellow

Fruiting

Throughout the year.

Propagation Technique

Easy from seed or hardwood cuttings. Seed germinates best if scarified and then soaked over night. An excellent winter to early spring flowering shrub for a coastal or lowland garden. Prefers full sun and free draining soil but will tolerate semi-shade. This species is usually short-lived (5-15 years), and it is wise to keep a few replacement plants going in pots just in case. Although it will tolerate snow and frost, it is better grown in warmer climates.

Threats

Flowers, fruits and seed are palatable to rats. Some populations are at risk from coastal erosion. Plants tend to be short-lived, and are often inflicted with lemon tree borer (Oeomona hirta). Because the species is principally bird-pollinated, by New Zealand honeyeaters, the loss of these pollinators may affect reproductive effort. Though previously ranked as Nationally Endangered on the basis of the loss of mainland populations and the limited extent of island populations, it is now ranked as Relict on the basis that the loss of (most) mainland populations was historical and the island populations appear stable